Hmmmmmmmm is his arm not still attached to his body on the second last page?

The bell revived it or made it grow back or whatever weird magic manga does

That's because his arm has been restored with that magical bell thing, it went like this
she said I love u -> he was shocked->she approached him, used the bell->kiss happened, arm healed->chapter ends and we're left hanging ╥﹏╥

Oh so she used the bell thingy already. Sorry it's not too clear to me on first read. Thank you people